Augustine's Curse was presumably a spell that could give an individual the power to shapeshift into different forms such as a bat, panther, wolf, mist, and bee swarm.

Willow Rosenberg used a reverse incantation of it to remove the powers of Toru and his pack after they stole the secret of Dracula's shapeshifting powers.[1]

However, after Dracula's revelation that the spells that gave him his shapeshifting powers were mere window-dressing in that they only strengthened his power of will,[2] the purpose of Augustine's Curse has become unclear.